Communication system

ABSTRACT

A system is disclosed in which a base station performs an Automatic Neighbour Relation (ANR) operation in relation to a Wireless Local Area Network (WLAN) and obtains, from a mobile communication device (UE) or a Mobility Management Entity (MME), the Transport Network layer (TNL) address associated with a WLAN Termination node of the WLAN for establishing a connection between the base station and the WLAN Termination node.

TECHNICAL FIELD

The present invention relates to a communication system. The inventionhas particular but not exclusive relevance to wireless communicationsystems and devices thereof operating according to the 3rd GenerationPartnership Project (3GPP) standards or equivalents or derivativesthereof. The invention has particular although not exclusive relevanceto automatic neighbour relation procedures.

BACKGROUND ART

The latest developments of the 3GPP standards are referred to as theLong Term Evolution (LTE) of Evolved Packet Core (EPC) network andEvolved Universal Mobile Telecommunications System (UMTS) TerrestrialRadio Access Network (E-UTRAN). Under the 3GPP standards, a NodeB (or aneNB in LTE) is the base station via which communication devices connectto a core network and communicate to other communication devices orremote servers. For simplicity, the present application will use theterm base station to refer to any such base stations.

Communication devices might be, for example, mobile communicationdevices such as mobile telephones, smartphones, user equipment, personaldigital assistants, laptop/tablet computers, web browsers, e-bookreaders and/or the like. Such mobile (or even generally stationary)devices are typically operated by a user. However, 3GPP standards alsomake it possible to connect so-called ‘Internet of Things’ (IoT) devices(e.g. Narrow-Band IoT (NB-IoT) devices) to the network, which typicallycomprise automated equipment, such as various measuring equipment,telemetry equipment, monitoring systems, tracking and tracing devices,in-vehicle safety systems, vehicle maintenance systems, road sensors,digital billboards, point of sale (POS) terminals, remote controlsystems and the like. IoT devices can be implemented as a part of a(generally) stationary apparatus such as vending machines, roadsidesensors, POS terminals, although some IoT devices can be embedded innon-stationary apparatus (e.g. vehicles) or attached to animals orpersons to be monitored/tracked. It will be appreciated that IoT devicesare sometimes also referred to as Machine-Type Communication (MTC)communication devices or Machine-to-Machine (M2M) communication devices.For simplicity, the present application refers to mobile devices in thedescription but it will be appreciated that the technology described canbe implemented on any communication devices (mobile and/or generallystationary) that can connect to a communications network forsending/receiving data, regardless of whether such communication devicesare controlled by human input or software instructions stored in memory.

Most mobile devices support other communication technologies than LTE,for example, a communication technology in accordance with the 802.11family of standards (commonly referred to as Wi-Fi). The 802.11standards have been specified by the Institute of Electrical andElectronics Engineers (IEEE) for use in wireless local area networks(WLANs).

Unlicensed spectrum (such as WLANs and/or the like) is becomingincreasingly important for cellular operators. In order to cater tooperators' demand, 3GPP have defined a number of WLAN interworkingfeatures, including the so-called LTE-WLAN Aggregation (LWA) and the LTEWLAN Radio Level Integration with IPsec Tunnel (LWIP).

Effectively, LWA (or more recently, the ‘enhanced LWA’ or ‘eLWA’)facilitates the interworking and radio level integration between LTEnetworks and WLANs by configuring a single bearer to utilise LTE andWLAN resources simultaneously. LWA is described in 3GPP technicalspecification (TS) 36.300 V13.3.0, section 22A.1, the contents of whichare incorporated herein by reference.

LWA supports two deployment scenarios:

-   -   Collocated—integrated LTE base station (eNB) and WLAN access        point (AP)/access controller (AC)    -   Non-collocated—eNB and WLAN AP/AC connected via a WLAN        Termination (WT) logical node using the interface Xw specified        by 3GPP

The Xw interface supports both control plane and data plane andterminates in the WT logical node.

LWA allows aggregating LTE and WLAN at radio access network (RAN) leveland the WLAN AP/AC interacts with the LTE base station (over Xw). TheE-UTRAN base station controls LWA for compatible user equipment (UE) inits cell, i.e. whether to use only LTE resources or both LTE and WLANresources, based on measurement reporting provided by the UE.

The base station configures a WLAN mobility set for each mobile devicefor which LWA is activated, based on e.g. WLAN measurements by thatmobile device. The WLAN mobility set is a group of WLAN APs (identifiedby their associated Service Set Identifier(s) and/or the like) and theWLAN mobility set is UE-specific. There is only one WLAN mobility setconfigured for a particular UE at a time, and all WLANs in theconfigured WLAN mobility set are connected to the same WT. Mobilitywithin WLAN mobility set is controlled by the mobile device, i.e.transparent to the base station. However, mobility outside the WLANmobility set is controlled by the base station.

SUMMARY OF INVENTION Technical Problem

However, it is not currently possible to establish an Xw connectionautonomously between a base station and a WLAN without significantlycomplicating base station functionality.

For example, a relatively complex, network-based solution has beenconsidered by 3GPP, which requires each base station to connect to adomain name system (DNS) lookup server in order to obtain the address ofthe WT before being able to set up an appropriate Xw connection withthat WT. This network-based solution is described in e.g. 3GPP TdocsR3-160345, R3-160323, and R3-160545, the contents of which areincorporated herein by reference. Further details of the network-basedsolution described in R3-160323 are shown in FIGS. 5 and 6.

Moreover, it is not currently clear how to enable inter eNB mobility(i.e. between different LTE base stations) where the affected UE isserved by a WLAN and there may, or may not be, a change in the servingWT as result of the UE's mobility.

Accordingly, preferred example embodiments of the present invention aimto provide methods and apparatus which address or at least partiallydeal with the above issues.

Although for efficiency of understanding for those of skill in the art,the invention will be described in detail in the context of a 3GPPsystem (UMTS, LTE), the principles of the invention can be applied toother systems in which communication devices or User Equipment (UE)access a core network using at least one radio access technology.

Solution to Problem

In one example aspect, the invention provides a base station for acommunication network, the base station comprising: a transceiverconfigured to communicate with a communication device; and a controllerconfigured to perform an automatic neighbour relation operation inrelation to at least one Wireless Local Area Network, WLAN; wherein thecontroller is configured to obtain, from at least one of thecommunication device and a mobility management entity, an addressassociated with a node of the wireless local area network, WLAN, and toestablish a connection with the node of the WLAN using the obtainedaddress.

In another example aspect, the invention provides a base station for acommunication network, the base station comprising: a transceiverconfigured to communicate with a neighbouring base station; and acontroller configured to obtain, from at least one of the neighbouringbase station and an access point of a wireless local area network, WLAN,information indicating that the neighbouring base station has a directconnection with a node of the WLAN.

In another example aspect, the invention provides a base station for acommunication network, the base station comprising: a transceiverconfigured to communicate with a neighbouring base station; and acontroller configured to obtain, from the neighbouring base station,information indicating that the neighbouring base station has a directconnection with a base station that is operable as a secondary basestation, SeNB, in a dual connectivity, DC, arrangement.

In one example aspect, the invention provides a mobility managemententity for a communication network, the mobility management entitycomprising: a controller configured to obtain, upon request by a basestation performing an automatic neighbour relation operation in relationto at least one wireless local area network, WLAN, an address associatedwith a node of the WLAN; and a transceiver configured to send, to thebase station, the obtained address associated with the node of the WLAN.

In another example aspect, the invention provides a communication devicefor a communication network, the communication device comprising: acontroller configured for obtaining, from an access point of a wirelesslocal area network, WLAN, information identifying an address of a nodeof the WLAN; and a transceiver configured to provide the obtainedinformation to the base station as part of an automatic neighbourrelation operation in relation to the WLAN.

In a further example aspect, the invention provides an access point fora communication network, the access point comprising a transceiverconfigured to broadcast an address of a node of a wireless local areanetwork (WLAN) to which the access point belongs.

Example aspects of the invention extend to corresponding systems,methods, and computer program products such as computer readable storagemedia having instructions stored thereon which are operable to program aprogrammable processor to carry out a method as described in the aspectsand possibilities set out above or recited in the claims and/or toprogram a suitably adapted computer to provide the apparatus recited inany of the claims.

Each feature disclosed in this specification (which term includes theclaims) and/or shown in the drawings may be incorporated in theinvention independently of (or in combination with) any other disclosedand/or illustrated features. In particular but without limitation thefeatures of any of the claims dependent from a particular independentclaim may be introduced into that independent claim in any combinationor individually.

Example embodiments of the invention will now be described, by way ofexample, with reference to the accompanying drawings in which:

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates schematically a cellular telecommunication system towhich example embodiments of the invention may be applied;

FIG. 2 is a block diagram of a mobile device forming part of the systemshown in FIG. 1;

FIG. 3 is a block diagram of a base station forming part of the systemshown in FIG. 1;

FIG. 4 is a block diagram of a mobility management entity forming partof the system shown in FIG. 1;

FIG. 5 illustrates a currently proposed network-based solution;

FIG. 6 illustrates a currently proposed network-based solution;

FIG. 7 is a timing diagram illustrating an exemplary way in whichexample embodiments of the invention can be implemented in the system ofFIG. 1;

FIG. 8 is a timing diagram illustrating an exemplary way in whichexample embodiments of the invention can be implemented in the system ofFIG. 1; and

FIG. 9 is a timing diagram illustrating an exemplary way in whichexample embodiments of the invention can be implemented in the system ofFIG. 1.

DESCRIPTION OF EMBODIMENTS Overview

FIG. 1 schematically illustrates a telecommunications network 1 in whichmobile devices 3 (mobile telephones and/or other user equipment) cancommunicate with each other via a mobile network operator (MNO) network2 using base stations 5 (e.g. LTE base stations or ‘eNB’) and a corenetwork (not shown in FIG. 1) using an appropriate E-UTRA radio accesstechnology (RAT). As those skilled in the art will appreciate, whilstthree mobile devices 3 and one base station 5 are shown in FIG. 1 forillustration purposes, the system, when implemented, will typicallyinclude other base stations and communication devices.

Each base station 5 operates one or more associated cells. Mobiledevices 3 connect to an appropriate cell (depending on their locationand possibly on other factors, e.g. signal conditions, subscriptiondata, capability, and/or the like) by establishing a radio resourcecontrol (RRC) connection with the base station 5 operating that cell.

The MNO network 2 also includes an Info/DNS service node 7 and amobility management entity (MME) 9 (amongst other things). The Info/DNSservice node 7 is responsible for storing respective transport networklayer (TNL) addresses associated with each network node of thetelecommunications network 1. The MME 9 is the network node responsiblefor keeping track of the locations of the mobile devices 3 within thecommunications network 1, and for assisting the serving base station 5in configuring the communication bearers used by mobile devices in thebase station's cell.

Each base station 5 is connected to the core network (MME 9) via an S1interface and neighbouring base stations are connected to each other viaan X2 interface. The core network (MNO network 2) typically alsoincludes one or more serving gateways (S-GWs) and packet data networkgateways (P-GWs) for providing a connection between the base stations 5and other networks (such as the Internet) and/or servers hosted outsidethe core network.

As can be seen, some mobile devices 3 are also able to connect to a WLAN12 (e.g. a WLAN 12A of ‘Hotspot Operator 1’ and/or a WLAN 12B of‘Hotspot Operator 2’) via an appropriate access point 15 of that WLAN12. The WLANs 12A and 12B (and hence the access points 15) are connectedto the base station 5 via a respective WT node 17A/17B.

When the base station 5 enables LWA functionality for a compatiblemobile device 3, the base station 5 configures the WLAN 12 via thecorresponding WT node 17 to communicate user data via one or more accesspoints 15 (simultaneously to communicating user data via the basestation 5).

The telecommunications network 1 makes beneficial use of an AutomaticNeighbour Relation (ANR) for LWA, for example, by utilising informationacquired during discovery of WLANs under a particular base station'scoverage (cell).

Specifically, in order to determine which WLAN 12 can be used by themobile device 3, i.e. which WLANs 12 are overlapping with the cell ofthe base station 5, the nodes of the telecommunications network 1 areconfigured with appropriate ANR functionality to enable an appropriateXw connection between the base station 5 and a WT node 17 associatedwith a neighbouring access point 15 to be setup autonomously withoutundue complexity (e.g. in an analogous way to establishing an X2connection between neighbouring base stations).

In more detail, in this system the base station 5 is configured toobtain an appropriate WLAN identifier (e.g. a Service Set Identifier(SSID), a Homogenous Extended Service Set Identifier (HESSID), a BasicService Set Identifier (BSSID), and/or the like) associated with eachneighbouring WLAN 12. In order to do so, the base station 5 is able toconfigure the mobile device 3 to carry out, and report, appropriate WLANmeasurements to allow detection of neighbouring access points 15 and toreport the WLAN identifier of detected WLANs 12/access points 15 to thebase station 5.

Based on the WLAN identifier, the base station 5 is configured to obtain(either from the MME 9 or from the mobile device 3) the TNL address ofthe WT node 17 that is associated with the WLAN identifier, i.e. the WTnode that belongs to the same WLAN 12 as the access point(s) 15 detectedby the mobile device 3. If the base station 5 obtains the TNL address ofthe WT node 17 from the MME 9, the MME 9 may be configured to perform anappropriate query with the Info Service (DNS/Fully Qualified Domain Name(FQDN)) node 7 in order to obtain the TNL address corresponding to theWLAN identifier reported by the mobile device 3. If the base station 5obtains the TNL address of the WT node 17 from the mobile device 3, thebase station 5 may configure the mobile device to obtain the TNL addressof the WT node 17 from information broadcast by the detected accesspoint 15 (and report the TNL address to the base station 5). Thebroadcasting of the WT address may be encrypted by the access point 15such that only allowed UEs (in this example, the mobile device 3) and/orthe base station 5 are able to decrypt the details.

Beneficially, using the obtained TNL address, the base station 5 is ableto autonomously connect to the appropriate WT node 17 and configure LWAfunctionality for the mobile device 3 via the neighbouring WLAN 12detected by the mobile device 3. There is no need for the base station 5to implement functionality for querying the Info Service (e.g. DNS) node7.

In a particularly beneficial example, neighbouring base stations 5 maybe configured to notify each other about the WT node(s) 17 used by them.For example, neighbouring base stations 5 may be configured to exchangeappropriate signalling messages including information identifying the WTnode 17 being used and/or any associated WLAN ID. Beneficially, theexchanged information may help a source base station select anappropriate target base station for the mobile device in case of ahandover.

Beneficially, therefore, a source base station is able to determinewhether the handover requires a change of the WT node as well, evenbefore triggering a handover, and the source base station knows whatinformation it needs to exchange with the target base station, dependingon handover type, in order to assist the operation of the target basestation and avoid or minimise the risk of a radio link failure for themobile device during handover.

Mobile Device

FIG. 2 is a block diagram illustrating the main components of the mobiledevice 3 shown in FIG. 1 (e.g. a mobile telephone or other userequipment). As shown, the mobile device 3 has a transceiver circuit 31that is operable to transmit signals to and to receive signals from abase station 5 via one or more antenna 33. The mobile device 3 has acontroller 37 to control the operation of the mobile device 3. Thecontroller 37 is associated with a memory 39 and is coupled to thetransceiver circuit 31. Although not necessarily required for itsoperation, the mobile device 3 might of course have all the usualfunctionality of a related mobile telephone 3 (such as a user interface35) and this may be provided by any one or any combination of hardware,software and firmware, as appropriate. Software may be pre-installed inthe memory 39 and/or may be downloaded via the telecommunicationsnetwork or from a removable data storage device (RMD), for example.

The controller 37 is configured to control overall operation of themobile device 3 by, in this example, program instructions or softwareinstructions stored within the memory 39. As shown, these softwareinstructions include, among other things, an operating system 41, acommunications control module 43, an LTE module 45, a WLAN module 47,and an ANR module 49.

The communications control module 43 is operable to control thecommunication between the mobile device 3 and its serving base station5/access point 15 (and other communication devices connected to theserving base station 5/access point 15, such as further mobile devicesand/or network nodes).

The LTE module 45 is responsible for communicating with base stations 5operating in accordance with 3GPP standards (e.g. LTE). The WLAN module47 is responsible for communicating with WLANs (one or more APs)operating in accordance with the 802.11 family of standards (e.g.Wi-Fi). When LWA is enabled for the mobile device 3, the mobile device 3communicates simultaneously using the LTE module 45 and the WLAN module47 in accordance with an associated LWA configuration provided by thebase station 5.

The ANR module 49 is responsible for procedures relating to automaticneighbour relations, including obtaining at least one of an SSID, anHESSID, a BSSID, and a TNL address associated with a WT node 17 to beadded as a neighbour for the base station 5 serving the mobile device 3.

Base Station

FIG. 3 is a block diagram illustrating the main components of a basestation 5 shown in FIG. 1. As shown, the base station 5 has atransceiver circuit 51 for transmitting signals to and for receivingsignals from the communication devices (such as mobile devices 3/userequipment) via one or more antenna 53, a core network interface 55 (e.g.an S1 interface) for transmitting signals to and for receiving signalsfrom the core network (e.g. MME 9), and a base station interface 56(e.g. an X2 interface) for transmitting signals to and for receivingsignals from neighbouring base stations. The base station 5 has acontroller 57 to control the operation of the base station 5. Thecontroller 57 is associated with a memory 59. Although not necessarilyshown in FIG. 3, the base station 5 will of course have all the usualfunctionality of a cellular telephone network base station and this maybe provided by any one or any combination of hardware, software andfirmware, as appropriate. Software may be pre-installed in the memory 59and/or may be downloaded via the communications network 1 or from aremovable data storage device (RMD), for example. The controller 57 isconfigured to control the overall operation of the base station 5 by, inthis example, program instructions or software instructions storedwithin the memory 59. As shown, these software instructions include,among other things, an operating system 61, a communications controlmodule 63, a measurement control module 65, a WLAN management module 67,an Xw module 68, and an ANR module 69.

The communications control module 63 is operable to control thecommunication between the base station 5 and mobile devices 3 (userequipment) and other network entities that are connected to the basestation 5. The communications control module 63 also controls theseparate flows of downlink user traffic (via associated data radiobearers) and control data to be transmitted to communication devicesassociated with this base station 5 including, for example, control datafor managing LWA operation and/or mobility of the mobile device 3.

The measurement control module 65 is responsible for configuringmeasurements (including WLAN measurements relating to LWA) for mobiledevices 3 connected to the base station 5 and for receiving andprocessing measurement results associated with such measurements. Basedon the obtained measurement results, the measurement control module 65assists other modules controlling LWA operation and/or mobility (e.g.handover) for the mobile devices 3.

The WLAN management module 67 is responsible for managing access toneighbouring WLANs for mobile devices 3 served by the base station 5,including controlling LWA functionality for compatible mobile devices 3.The WLAN management module 67 is also responsible for maintaining anappropriate WLAN mobility set for each LWA enabled mobile device 3.

The Xw module 68 is responsible for communicating with neighbouring WTnodes 17 using the Xw application protocol (Xw-AP). Although not shownin FIG. 3, the base station may also comprise an appropriate X2 modulefor communicating with neighbouring base stations using the X2application protocol (X2-AP).

The ANR module 69 is responsible for procedures relating to automaticneighbour relations, including obtaining at least one of anSSID/HESSID/BSSID associated with an access point 15 and a TNL addressassociated with a WT node 17 to be added as a neighbour for the basestation 5.

Mobility Management Entity

FIG. 4 is a block diagram illustrating the main components of themobility management entity (MME) 9 shown in FIG. 1. As shown, themobility management entity 9 has a transceiver circuit 71 fortransmitting signals to and for receiving signals from the base stations5 (and/or communication devices connected to the base stations 5) via abase station interface 75 (e.g. an S1 interface). The mobilitymanagement entity 9 has a controller 77 to control the operation of themobility management entity 9. The controller 77 is associated with amemory 79. Although not necessarily shown in FIG. 4, the mobilitymanagement entity 9 will of course have all the usual functionality of acellular telephone network mobility management entity and this may beprovided by any one or any combination of hardware, software andfirmware, as appropriate. Software may be pre-installed in the memory 79and/or may be downloaded via the communications network 1 or from aremovable data storage device (RMD), for example. The controller 77 isconfigured to control the overall operation of the mobility managemententity 9 by, in this example, program instructions or softwareinstructions stored within the memory 79. As shown, these softwareinstructions include, among other things, an operating system 81, acommunications control module 83, a configuration transfer module 85,and a query module 86.

The communications control module 83 is operable to control thecommunication between the mobility management entity 9 and the basestations 5 (including mobile devices 3 connected to the base stations 5)and other network entities that are connected to the mobility managemententity 9.

The configuration transfer module 85 is responsible for handling(generating, sending, receiving) messages relating to the transfer ofANR configuration data between the MME 9 and a connected base station 5.For example, the configuration data may include at least one of anSSID/HESSID/BSSID associated with an access point 15 and a TNL addressassociated with a WT node 17.

The query module 86 is responsible for querying an informationservice/DNS node for ANR procedures relating to LWA. For example, thequery module 86 may use Fully Qualified Domain Name (FQDN) proceduresand/or Access Network Query Protocol (ANQP) procedures to obtain a TNLaddress associated with a WT node 17 to be added as a neighbour for abase station 5 connected to the MME 9.

In the above description, the mobile device 3, the base station 5, andthe mobility management entity 9 are described for ease of understandingas having a number of discrete modules (such as the communicationscontrol modules and the ANR modules). Whilst these modules may beprovided in this way for certain applications, for example where anexisting system has been modified to implement the invention, in otherapplications, for example in systems designed with the inventivefeatures in mind from the outset, these modules may be built into theoverall operating system or code and so these modules may not bediscernible as discrete entities. These modules may also be implementedin software, hardware, firmware or a mix of these.

A more detailed description will now be given (with reference to FIGS. 5to 8) of the scenario discussed above where a mobile device isconfigured for LWA by its serving base station, and where ANR andmobility procedures are provided autonomously.

Network-Based Approach

For completeness, FIGS. 5 and 6 illustrate a currently proposednetwork-based ANR approach in accordance with 3GPP Tdoc no. R3-160323.

As can be seen, the base station 5 (eNB) needs to connect to an ‘InfoService’ (e.g. a DNS lookup server and/or the like) in order to obtainthe address of the WT node 17 before the base station 5 is able to setup an appropriate Xw connection with that WT node 17. The Info Servicemay be a DNS Lookup Server although this requires a domain name to beassigned together with an FQDN, ANQP, and/or Generic AdvertisementService (GAS) capability on the eNB side. Similar functionality isconventionally carried out by the MME 9 (e.g. for ANR relating toneighbouring base stations) and it may not be feasible and/or practicalto implement this functionality in each eNB (e.g. because it may not bescalable).

Operation—First Example

FIG. 7 is a timing diagram (message sequence chart) illustrating anexample process performed by components of the system 1 when performingan ANR procedure for setting up an Xw connection between a base station5 (eNB) and a WT node 17.

Initially, as generally shown in step S1, the base station 5 (using itsmeasurement control module 65) configures the mobile device 3 (UE) tomeasure the WLAN(s) 12 in the vicinity of the mobile device 3. Themobile device 3 carries out appropriate measurements (using its WLANmodule 47), then using its LTE module 45 the mobile device 3 generatesand sends, in step S2, an appropriately formatted WLAN measurementreport to the base station 5. As can be seen, the WLAN measurementreport includes an appropriate SSID/HESSID/BSSID associated with eachmeasured access point 15 (obtained using the mobile device's ANR module49). It will be appreciated that the WLAN measurement report maycomprise an appropriately formatted ‘SON Configuration Transfer’ messageand the respective SSID/HESSID/BSSID associated with each measuredaccess point 15 may be included in a suitable information element (IE),for example, a ‘Target AP-ID List’ IE as shown in Table 1 below.

In this example, the mobile device 3 found an access point 15 of a WLAN12 that is not yet configured for the base station 5 as a neighbourWLAN. The new access point 15/WLAN 12 is identified by itsSSID/HESSID/BSSID included in the measurement report sent at step S2.

In order to set up the WT node 17 of the identified access point 15/WLAN12 as a neighbour, the base station 5 generates (using its ANR module69) and sends, in step S3, an appropriately formatted message to the MME9 (e.g. an eNB configuration transfer message and/or other suitable S1message) and includes in this message the SSID/HESSID/BSSID associatedwith the access point 15.

In response to this message, the MME 9 proceeds to obtain a TNL addressassociated with the WT node 17 that belongs to the same WLAN 12 as theaccess point 15 identified by the SSID/HESSID/BSSID in the eNBconfiguration transfer message. In this example, the MME 9 generates(using its query module 86) and sends, in step S4, an appropriatelyformatted message (e.g. an FQDN query) to the info service node 7 (e.g.a DNS lookup server/ANQP node) requesting the TNL address associatedwith the WT node 17. As generally shown in step S5, the info servicenode 7 returns an appropriate response to the MME's query, including theTNL address associated with the WT node 17 (of the WLAN 12 of the accesspoint 15 identified by the SSID/HESSID/BSSID). The response from theinfo service node 7 may also include information identifying whether thedetected access point 15/WT node 17 supports LWA, whether the WLAN 12has any access restriction, an associated public land mobile network(PLMN)-ID, and/or the like.

Alternatively, the MME 9 might retrieve the TNL address from its localmemory 79 (e.g. if the TNL address is already available at the MME 9).Therefore, steps S4 and S5 are optional (or they may be performed priorto step S3).

Once the MME 9 has retrieved the TNL address of the WT node 17 (from theinfo service node 7 or local memory 79), the MME 9 generates (using itsconfiguration transfer module 85 and sends, in step S6, an appropriatelyformatted message to the base station 5 (e.g. an MME configurationtransfer message and/or other suitable S1 message) and includes in thismessage the TNL address associated with the WT node 17. The MME 9 mayalso include in this message information identifying the WT node 17(e.g. a WT ID) and/or information identifying each BSSID, HESSID, and/orSSID supported by the WT node 17. If the MME 9 determines that thedetected access point 15/WT node 17 does not support LWA and/or thisparticular WLAN 12 is not accessible for users of the MNO network 2,then the MME 9 may be configured to send, to the base station 5, anappropriate indication to this effect (e.g. LWA not supported, WLANaccess restricted, TNL address not available, and/or the like).

It will be appreciated that the message sent at step S3 and/or step S6may comprise an appropriately formatted ‘X2 TNL Configuration Info’message, and the respective SSID/HESSID/BSSID associated with eachaccess point 15 and the TNL address of the WT node 17 may be included insuitable IEs of the ‘X2 TNL Configuration Info’ message. For example,the TNL address of the WT node 17 may be included in a ‘WT TransportLayer Address’ IE and the SSID/HESSID/BSSID associated with a particularaccess point 15 may be included in a ‘Supported BSSID, HESSID-,SSID-List’ IE as shown in Table 2. It will be appreciated that theSSID/HESSID/BSSID associated with each access point 15 is preferablysent as a list mainly because the mobile device 3 may have identifiedmore than one BSSID that belong to more than one WT node 17.

Using the TNL address received in step S6, the base station 5 generates(using its Xw module 68) and sends, in step S7, an appropriatelyformatted Xw signalling message (e.g. an Xw setup request) to the WTnode 17 in order to initiate setting up of an Xw connection with the WTnode 17. In step S8, the WT node 17 generates and sends an appropriateresponse (e.g. an Xw setup response and/or the like), in which itconfirms that the Xw connection has been set up with the base station 5(or the WT node 17 returns an appropriate failure notification to thebase station 5 if the Xw connection cannot be set up).

When the Xw connection is successfully set up between the base station 5and the WT node 17, the ANR configuration procedure is complete, and thebase station 5 may use the access points 15 connected to this WT node 17for (e)LWA for compatible mobile devices. For example, the accesspoint(s) 15 identified by the SSID/HESSID/BSSID (reported in step S2)can now be included in the WLAN mobility set for the mobile device 3.

Beneficially, in this example, there is no need to enable every basestation to connect to a special info/DNS server for ANR operation.Therefore, there is no need for the base station to be configured withFQDN, ANQP, and/or GAS functionalities (which in turn may result in asimplified base station design).

TABLE 1 SON Configuration Transfer (when applied to e.g. section9.2.3.26 of 3GPP TS 36.413) IE type and Semantics Assigned IE/Group NamePresence Range reference description Criticality Criticality SONConfiguration Transfer >Target AP-ID List 0 . . . <maxnoofWLAN AP> >>SSID O 9.2.1.x1 >> HESSID O 9.2.1.x2 >> BSSID O 9.2.1.x3 >Target eNB-IDO >>Global eNB ID M 9.2.1.37 >>Selected TAI M TAI 9.2.3.16 >SourceeNB-ID M >>Global eNB ID M 9.2.1.37 >>Selected TAI M TAI 9.2.3.16 >SONInformation M 9.2.3.27 >X2 TNL C- 9.2.3.29 Source eNB X2 TNL YES ignoreConfiguration Info ifSONInformationRequest ConfigurationInfo. >Synchronisation C-if Activate 9.2.3.42 Information on cell YESignore Information Muting selected as source of synchronisation andaggressor cells. Range bound Explanation maxnoofWLAN AP Maximum no. ofWLAN AP per node per RAT.

TABLE 2 X2 TNL Configuration Info (when applied to e.g. section 9.2.3.29of TS 36.413) IE type and Semantics Assigned IE/Group Name PresenceRange reference description Criticality Criticality eNB X2 Transport 1 .. . Layer Addresses <maxnoofeNBX2TLAs> >Transport Layer M 9.2.2.1Transport Layer Address Addresses for X2 SCTP end-point. eNB X2 Extended0 . . . YES Ignore Transport Layer <maxnoofeNBX2ExtTLAs>Addresses >IP-Sec Transport O 9.2.2.1 Transport Layer — — Layer AddressAddresses for IP-Sec end-point. >eNB GTP 0 . . . — — Transport Layer<maxnoofeNBX2GTPTLAs> Addresses >>GTP M 9.2.2.1 GTP Transport Layer — —Transport Layer Addresses for GTP Address end-points (used for dataforwarding over X2). eNB Indirect X2 0 . . . YES Ignore Transport Layer<maxnoofeNBX2TLAs> Addresses >Transport Layer O 9.2.2.1 Transport LayerAddress Addresses for Indirect X2 SCTP end-point. WT Xw Transport 0 . .. YES ignore Layer Addresses <maxnoofWLANAP> List >WT ID M 9.2.2.yUnique WT ID >WT Transport M 9.2.2.1 Transport Layer Layer AddressAddresses for X2 SCTP end-point. >Supported BSSID, HESSID- SSID-List >>HESSID 9.2.1.x1 >> BSSID 9.2.1.x2 >> SSID 9.2.1.x3

In summary, the above example provides at least some of the followingbenefits:

Ensures network (MME) control, thus the base station cannot arbitrarilyconnect to any WT node. This operation is preferred by MNOs.

Scalable: there is no need to connect every base station to an externalDNS server and ANR operation is kept simple on the base station's side.

It is estimated that there may be several million base stations deployedby various MNOs, each of which base stations need to be configured andupgraded regularly. Scalability is therefore important for MNOs.

There is no need to make each base station FQDN capable. Neither thebase station (eNB) nor the mobile device (UE) are required to supportGAS and/or ANQP functionality.

In this example, only the MME is required to support FQDN/ANQP/GAS(which may be already supported by the MME for other purposes). Theprovision of a (single) secure connection between the MME and the Infoservice is less expensive compared to the provisioning of (multiple)secure connections between each base station and Info Servers.

Security: there is no need to expose the TNL address of a centralizedInfo Service to every network node (including potentially malicious orincorrectly configured (H)eNBs/WT nodes) thereby user plane traffic isnot compromised. There is also no issue with using a network addresstranslator (NAT).

Operation—Second Example

FIG. 8 is a timing diagram (message sequence chart) illustrating anotherexample process performed by components of the system 1 when performingan ANR procedure for setting up an Xw connection between a base station5 (eNB) and a WT node 17. In this example, the base station 5 isconfigured to obtain the TNL address of the WT node 17 from the mobiledevice 3.

It will be appreciated that each WLAN AP 15 that supports LWA broadcastsone or more of the following information (e.g. in addition to theSSID/HESSID/BSSID associated with that access point):

-   -   information (e.g. a PLMN-ID) identifying a public land mobile        network (PLMN) associated with the WLAN 12/access point 15;    -   information identifying that the WLAN 12/access point 15        supports LWA functionality (e.g. an appropriate ‘LWA-Support        Indicator’ IE/flag);    -   information (e.g. a WT ID) identifying the WT node 17 associated        with the access point 15; and    -   the TNL Address of the WT node 17 associated with the access        point 15.

For example, the access points may use an appropriately formattedtransparent container (e.g. as defined in Annex H of 3GPP TS 24.302V13.5.0) for broadcasting the above information.

The procedure begins in step S11 which corresponds to step S1 describedabove with reference to FIG. 7. In step S11, the serving base station 5configures the mobile device 3 to measure the WLAN(s) 12 in the vicinityof the mobile device 3. After appropriate measurements the mobile device3 generates and sends, in step S12, a WLAN measurement report to thebase station 5. In this example, the WLAN measurement report includesthe WLAN AP ID (e.g. SSID/HESSID/BSSID) associated with the detectedaccess point 15.

If the WLAN AP ID is not recognised by the base station 5 as a neighbour(e.g. not stored in its WLAN management module 67/ANR module 69), thenthe base station 5 proceeds to generate (using its measurement controlmodule 65) and send, in step S13, an appropriately formatted signallingmessage to the mobile device 3 requesting the mobile device 3 to readthe LWA information broadcast by the access point 15 (e.g. theLWA-Support Indicator, WT ID, and/or TNL address of the WT node 17). Itwill be appreciated that the access point 15 may use an LWA-specificencryption when broadcasting the information, thus the mobile device 3may need to decrypt the information if appropriate.

The mobile device 3 (using its ANR module 49) reads the requestedparameters (the information broadcast by the access point 15 such as theLWA-Support Indicator, WT ID, and/or TNL address of the WT node 17),then in step 14, the mobile device 3 generates (using its LTE module 45)and sends an appropriate signalling message and reports the requestedparameters to the base station 5. It will be appreciated that the mobiledevice 3 may not need to decrypt the LWA information broadcast by theaccess point 15. Instead, the mobile device 3 may be configured to sendthe captured information to the base station 5 (for decrypting andprocessing by the base station 5).

In steps S17 and S18 (which correspond to steps S7 and S8,respectively), the base station 5 establishes an Xw connection towardsthe detected WT node 17, using the parameters (TNL address, etc.)provided by the mobile device 3.

Beneficially, this ‘UE-based’ example does not require connecting to anInfo/DNS service node or ANQP server for looking up the TNL address ofthe WT node 17.

Operation—Mobility

As explained in the introduction, it is not currently clear how toenable inter eNB mobility (i.e. between different LTE base stations)where the affected UE is served by a WLAN and there may, or may not be,a change in the serving WT as result of the UE's mobility. The inventorshave realised that before triggering a handover, the source base stationis unable to determine whether the handover requires a WT change or not.This is because different types of information need to be exchangedbetween the source and target base station depending on handover type(i.e. with or without WT change).

As mentioned above, in case of a handover between base stations 5, thehandover may involve changing the WT node 17 that is involved with theLWA service configured for the mobile device 3 being handed over.

Beneficially, in this example, the source base station 5 is able todetermine whether the handover requires a change of the WT node 17,before triggering a handover.

This is possible because in this system neighbouring base stations 5 areconfigured to notify each other about each WT node 17/WLAN 12 they use.For example, the base stations 5 may be configured to exchangeappropriate signalling messages (e.g. X2 Setup and/or ConfigurationUpdate messages shown in Table 3) including information identifying anyWT node 17 being used and/or any associated WLAN ID (e.g. a ‘WT List’ IEand/or the like). Alternatively, the WT nodes 17 may be configured tonotify their neighbouring base stations 5 when they establish an Xwconnection with a new base station.

In more detail, as generally illustrated in step S21 of FIG. 9, the WTnode 17 and a base station 5A may establish an Xw connection (forexample, as described above with reference to FIG. 7 or 8).

Following the establishment of the Xw connection, there are two options.In ‘option A’, which is illustrated in step S22 a, the base station 5Agenerates and sends an appropriate signalling message (e.g. an ‘X2Setup’ message or an ‘X2 Configuration Update’ message) to its neighbourbase station 5B. In ‘option B’, which is illustrated in step S22 b, theWT node 17 generates and sends an appropriate signalling message (e.g.an ‘Xw Setup’ request/response message, an ‘Xw Configuration Update’message, or a ‘WT Configuration Update’ message) to the base station 5B(assuming that the WT node 17 and the base station 5B are connected).The signalling message includes, in a suitable information element,information identifying the WT node 17 and/or the identifier(s) (e.g.one or more SSID/BSSID/HESSID) associated with the WLAN 12 that the WTnode 17 forms part of.

As generally shown in step S23, if the neighbour base station 5B is notyet connected to the WT node 17, they may proceed to establish an Xwconnection based on the information provided by the base station 5A(e.g. after obtaining the TNL address of the WT node 17 from the MME 9,as described above with reference to steps S3 to S6 of FIG. 7).

Therefore, when the base station 5B serving the mobile device 3 (whilstLWA is active) is beneficially able to use the obtained informationabout the neighbouring base station's WT connectivity in its mobilitydecision (step S24).

Beneficially, therefore, the base station 5B (when acting as a sourceeNB) knows in advance whether or not the handover (e.g. to base station5A) involves a change of WT node 17 and hence the source base station 5Bknows which target base station to choose in order to minimise the riskof a radio link failure (RLF) and to ensure a sufficient Quality ofExperience (QoE) for the mobile device 3 in case of a handover. Forexample, if the source base station 5B is configured to make a handoverdecision based purely on radio conditions, it may choose a target basestation that does not have the same WT connectivity. In this case, itmay be better to choose a target base station that has the same WTconnectivity (assuming that the target's radio conditions arecomparable).

The base station 5B also knows the type of information it needs toexchange with the target base station (e.g. base station 5A) dependingon handover type (i.e. with or without WT change).

TABLE 3 X2 Setup and Configuration update IE type and Semantics AssignedIE/Group Name Presence Range reference description CriticalityCriticality Message Type M 9.2.13 YES reject Global eNB ID M 9.2.22 YESreject Served Cells 1 . . . Complete list of cells YES reject<maxCellineNB> served by the eNB >Served Cell M 9.2.8 — —Information >Neighbour 0 . . . — — Information<maxnoofNeighbours> >>ECGI M ECGI E-UTRAN Cell Global — — 9.2.14Identifier of the neighbour cell >>PCI M INTEGER Physical CellIdentifier of — — (0 . . . 503, . . .) the neighbour cell >>EARFCN M9.2.26 DL EARFCN for FDD or — — EARFCN for TDD >>TAC O OCTET TrackingArea Code YES ignore STRING (2) >>EARFCN O 9.2.65 DL EARFCN for FDD orYES reject Extension EARFCN for TDD. If this IE is present, the valuesignalled in the EARFCN IE is ignored. WT List 0 . . . <maxWT> > WT ID M9.2.6 of TS 36.463 > Detected WLAN 0 . . . 1 AP List >> SSID O >> BSSIDM >> HESSID O GU Group Id List List of all the pools to GLOBAL rejectwhich the eNB belongs > GU Group Id M 9.2.20 — — LHN ID O 9.2.83 YESignore

Modifications and Alternatives

Detailed example embodiments have been described above. As those skilledin the art will appreciate, a number of modifications and alternativescan be made to the above example embodiments whilst still benefitingfrom the inventions embodied therein. By way of illustration only anumber of these alternatives and modifications will now be described.

In the above example embodiments, the base station uses a 3GPP radiocommunications (radio access) technology to communicate with the mobiledevice. However, any other radio communications technology (i.e. WLAN,Wi-Fi, WiMAX, Bluetooth, etc.) can be used for managing transmissions ofmobile devices in accordance with the above embodiments. The aboveexample embodiments are also applicable to ‘non-mobile’ or generallystationary user equipment.

In the above example embodiments, access points (APs) are used asexemplary WLAN nodes. However, it will also be appreciated that accesscontrollers (ACs) may also be used in the WLANs and in this case themobile device may be configured to detect and report access controllersto the serving base station.

In the above example embodiments, the LWA capable mobile device isdescribed to carry out WLAN measurements. 3GPP TS 36.300 specifies thateach UE (mobile device) supporting LWA may be configured by the E-UTRAN(base station) to perform WLAN measurements. A WLAN measurement objectcan be configured using WLAN identifiers (BSSID, HESSID, and SSID), WLANchannel number, and WLAN band. WLAN measurement reporting is triggeredusing received signal strength indicator (RSSI). WLAN measurement reportmay contain RSSI, channel utilization, station count, admissioncapacity, backhaul rate, and WLAN identifier.

Thus, it will be appreciated that the measurement configuration (e.g.steps S1 and S11) from the base station may include: WLAN ids, WLANband, and/or frequency/channel to be measured. It will also beappreciated that the WLAN measurement report (e.g. steps S2 and S12)from the mobile device may include: WLAN ids, RSSI, STA count, backhaulrate, admission capacity, channel utilization, and/or other metrics.

3GPP have defined the following WLAN measurement events:

-   -   Event W1: WLAN becomes better than a threshold;    -   Event W2: All WLAN inside WLAN mobility set become worse than a        threshold1 and a WLAN outside WLAN mobility set becomes better        than a threshold2;    -   Event W3: All WLAN inside WLAN mobility set become worse than a        threshold.

In the above description of FIG. 7, the base station is described tosend an eNB configuration transfer message and/or other suitable S1message and includes in this message (e.g. in an appropriate informationelement thereof) the SSID/HESSID/BSSID associated with the detectedaccess point. However, it will also be appreciated that other messagesmay also be used, for example, a WT address discovery message and/or thelike.

In the above description of FIG. 9, the base stations are described toexchange information about their WT node connectivity. It will beappreciated that the exchanged information may include informationidentifying whether a particular base station has a direct Xw connectionwith a WT node (LWA case) and/or whether a particular base station has adirect X2 connection with another base station (e.g. a base stationconfigurable as a secondary base station in a dual connectivityscenario). Table 4 illustrates an exemplary information element of theX2 Setup/Configuration update message that may be used for this purpose.It will be appreciated that the information exchanged between the basestations may be used in selection of an appropriate target base station(e.g. both in LWA and dual connectivity scenario).

TABLE 4 X2 Setup/Configuration update information elements >NeighbourInformation >>ECGI M >>PCI M >>EARFCN M >>TAC O >>EARFCN ExtensionO >>has X2 Yes/No

In the above description, the mobile device, the base station, and theMME are described for ease of understanding as having a number ofdiscrete functional components or modules. Whilst these modules may beprovided in this way for certain applications, for example where anexisting system has been modified to implement the invention, in otherapplications, for example in systems designed with the inventivefeatures in mind from the outset, these modules may be built into theoverall operating system or code and so these modules may not bediscernible as discrete entities.

In the above example embodiments, a number of software modules weredescribed. As those skilled in the art will appreciate, the softwaremodules may be provided in compiled or un-compiled form and may besupplied to the base station, to the mobility management entity, or tothe mobile device as a signal over a computer network, or on a recordingmedium. Further, the functionality performed by part or all of thissoftware may be performed using one or more dedicated hardware circuits.However, the use of software modules is preferred as it facilitates theupdating of the base station, the mobility management entity, or themobile device in order to update their functionalities.

The controller of the base station may be configured to control, usingthe established connection, aggregation of resources for concurrentcommunications via a cell operated by the base station and via an accesspoint of the WLAN.

The controller of the base station may be configured to obtain, from themobility management entity, the address associated with a node of a WLANby sending, to the mobility management entity, a signalling message fortriggering transfer of the address associated with the node of the WLAN(e.g. an ‘eNB Configuration Transfer’ message or a ‘WT AddressDiscovery’ message).

The controller of the base station may be configured to obtain, from thecommunication device, the address associated with a node of a WLAN bysending, to the communication device, a message to request that thecommunication device reads the address of the node of the WLAN (readingWLAN information broadcast).

The signalling message may include an identifier for identifying theWLAN, for example, a Service Set Identifier (SSID); a HomogenousExtended Service Set Identifier (HESSID); and/or a Basic Service SetIdentifier (BSSID).

The address may comprise a transport network layer (TNL) address.

The controller of the base station may be further configured to obtainat least one of: information (e.g. a ‘WT ID’) identifying a node of theWLAN, a list of access points of the WLAN; and an identifier foridentifying the WLAN (for example, a Service Set Identifier (SSID); aHomogenous Extended Service Set Identifier (HESSID); and/or a BasicService Set Identifier (BSSID)).

The request by the base station to the mobility management entity maycomprise a signalling message for triggering transfer of the addressassociated with the node of the WLAN (e.g. an ‘eNB ConfigurationTransfer’ message or a ‘WT Address Discovery’ message).

The controller of the mobility management entity may be configured toobtain the address associated with the node of the WLAN from aninformation service or domain name system node (e.g. using anappropriate Fully Qualified Domain Name (FQDN) procedure and/or anAccess Network Query Protocol (ANQP) procedure).

The controller of the communication device may be further configured foraggregation of resources for concurrent communications via a celloperated by the base station and via an access point of the WLAN.

The transceiver of the communication device may be configured toreceive, from the WLAN, an identifier for identifying the WLAN; and toprovide the received identifier to the base station in a measurementreport.

The transceiver of the communication device may be configured toreceive, from the base station after sending the measurement report, amessage to request that the communication device reads the address of anode of the WLAN identified by the identifier; and wherein thecontroller is configured to perform said obtaining of the address of thenode of the WLAN in response to the request message.

The message may be further configured to request that the communicationdevice reads at least one of: information (e.g. a PLMN-ID) identifying apublic land mobile network (PLMN) associated with the WLAN; informationidentifying that the access point supports LTE-WLAN Aggregation (LWA)functionality (e.g. an ‘LWA-Support Indicator’); and information (e.g. a‘WT ID’) identifying the node of the WLAN.

The communication device may be configured to obtain at least one of:the information identifying a PLMN associated with the WLAN; theinformation identifying that the access point supports LWAfunctionality; and the information identifying the node of the WLAN.

The transceiver of the access point may be further configured tobroadcast at least one of: information (e.g. a PLMN-ID) identifying apublic land mobile network, PLMN, associated with the WLAN; informationidentifying that the access point supports LTE-WLAN Aggregation, LWA,functionality (e.g. an ‘LWA-Support Indicator’); and information (e.g. a‘WT ID’) identifying the node of the WLAN.

Various other modifications will be apparent to those skilled in the artand will not be described in further detail here.

The following is a detailed description of the ways in which the abovedescribed automatic neighbour relation embodiments may be implemented inthe currently proposed 3GPP standards. Whilst various features aredescribed as being essential or necessary, this may only be the case forthe proposed 3GPP standard, for example due to other requirementsimposed by the standard. These statements should not, therefore, beconstrued as limiting the present invention in any way.

1 Introduction

As the name implies, the intention of ANR is to minimise configurationeffort of an operator especially for establishing relationship betweenneighbours. Given the billions of WiFi Access Points out there havingrelatively smaller coverage when compared to their LTE counterparts, ANRwill play an important role in relieving operator from substantialconfiguration that is otherwise required, ANR will help an eNB identifyits WiFi neighbour nodes through the neighbour relation table (NRT)creation, for providing better service to end customers. ANR consists ofWT TNL address lookup and subsequent establishment of Xw interface.Security and Scalability will be the utmost decision-making factors whenworking on solutions given the sheer size and non-operator deployednature of access points that roughly work on the same ISM band.

This paper discusses in terms of how to make ANR reliable and robust byconsidering a number of design factors.

2 Discussion

In Rel-13 LWA work, it may have been implied that neighbour relationsare formed mainly using OAM (Operation, Administration, and Maintenance)as opposed to through RRC measurement reporting. Unlike in LTE case,there is a need for a UE and eNB to steer clear of those that do notbelong to an Operator and that do not support LWA. If this informationis not there, the ANR will result in a tiring exercise for a UE as wellas to an eNB. Hence, it is important to decide on what needs to bebroadcast by an AP that supports LWA. The following is thus at leastrequired to be broadcast by an AP:

-   -   i) PLMN-ID    -   ii) LWA Support Indicator

It is hence important to decide whether LWA AP needs to have a Specialbehaviour in terms of what information it includes in its beacons.

Observation 1:

Including new Information in LWA AP beacons can minimise effort requiredby UE and eNB as part of ANR exercise.

Proposal 1:

RAN2/RAN3 is respectfully requested to explore whether augmenting LWA APbeacons is possible through collaborating with IEEE 802.11Standardisation bodies.

With extra pieces of Information being included in AP beacons, a UE cannow report only those relevant AP Identities (e.g., BSSID, HESSID, SSID)to an eNB for ANR purposes. Unlike in LTE, it is required for an eNB inLWA to first identify the mapping OR relationship between a detected APID and a WT ID and fetch corresponding TNL address of WT before it canestablish Xw with a relevant WT. In order to deal with this, presenteddifferent network-based and UE-based solutions were presented afteracknowledging the huge OAM effort being required on an operator unlessthis process is automated.

A network-based solution is presented in R3-160323 that requires eacheNB to connect to an Info Service to figure out AP-WT relationship andsubsequently to get TNL Address of the relevant WT. For this purpose,each eNB need to be capable of supporting FQDN functionality to triggerDNS-like query. Further connecting each eNB (more than 1 million incountries like China) to such an Info Service will not be scalable. Inaddition ensuring secure connection between each eNB and an Info Serviceafter authentication can be expensive.

Observation 2:

Connecting each eNB (more than 1 million in big countries) to an InfoService can lead to huge OPEX/CAPEX to an operator.

In the light of this burden to any operator that wants to support LWA,this paper presents a UE-based as well as a network-based Solutions todeal with Scalability and security issues.

2.1 Network-Based Solution:

Although radio agnostic, an MME gets involved in disseminating TNLaddresses of a target eNB in the LTE ANR process. This means that theinitial LTE design is not really in favour of allowing an eNB to connectto a DNS-server functionality for the purpose of fetching a TNL addressbelonging to a detected neighbour. Although this can increase corenetwork signalling, this mechanism ensures that E-UTRAN nodes contact acore node for retrieving information regarding another E-UTRAN node forscalability and security reasons. This need is paramount in the case ofLWA because WiFi hotspots are not always mobile network operator (MNO)deployed—but may belong to a different Hotspot Operator (HSO).

Observation 3:

Involving an MME in WT address discovery will make any Signalling-basedSolution Scalable and Secure.

Accordingly, an MME gets involved in each TNL Address discovery and as aresult there is no need to maintain connection between each eNB and anInfo Service. This can relieve an MNO as upgrading an MME can beconsidered as a natural evolution and relatively easy and scalable whencompared to connecting each eNB to an Info Service and upgrading eacheNB with new functionalities. As shown in FIG. 7, eNB/MME ConfigurationTransfer messages can be augmented or completely new messages can beused for this purpose that can enable an eNB to inquire more than oneBSSID, HESSID OR SSID and in return an MME supplies TNL addressesbelonging to more than one WT. Further, each WT is an MNO controlledentity and hence, authenticating using MME is readily possible. Hence,MME involvement will ensure that an eNB does not connect to anyarbitrary WT that is unknown to the network.

Proposal 2:

RAN3 is respectfully requested to explore whether MME involvement in WTTNL Address discovery is paramount to ensure security and scalability.

2.2 UE-Based Solution:

In order to minimize LWA impact on LTE network, a UE-based solution thatenables an eNB to get WT TNL Address can be helpful. A differentUE-based solution that requires each UE to inquire an ANQP Server forthe purpose of getting WT address has been previously presented. Itrequires big effort and capabilities such as GAS for a UE to query an APwhich has not been associated with.

Observation 4:

Querying an AP before getting associated by a UE cannot be reallypreferred.

As a natural evolution of the current ANR, each UE can be requested toincrementally gather details of an AP by an eNB. As part of this, an LWAAP may be configured to broadcast its WT relationship and WT TNL Addressin a secure way with proper encryption in place. With a UE supplied WTTNL Address, an eNB can readily establish Xw with no need of connectingLTE network to any Info Service.

Pros:

-   -   No major network impact hence, OPEX/CAPEX (capital        expenditure/operational expenditure) is less    -   Less OAM configuration

Cons:

-   -   New UE behaviour.    -   need to have secure mechanism in place for broadcasting WT        details

Observation 5:

A UE-based Solution is Simpler only if it can be made Secure.

Proposal 3:

RAN3 is respectfully requested to analyse the pros and cons of theUE-based and the network-based in terms of cost, scalability andsecurity and choose the right Solution.

3 Conclusion and Proposals

This paper Analyses the need for fully scalable and secure WT TNLAddress discovery and analyses two solutions in this regard. With itsbasic Analysis, it further makes the following Observations andproposals:

Observation 1:

Including new Information in LWA AP beacons can minimise effort requiredby UE and eNB as part of ANR exercise.

Proposal 1:

RAN2/RAN3 is respectfully requested to explore whether augmenting LWA APbeacons is possible through collaborating with IEEE 802.11Standardisation bodies.

Observation 2:

Connecting each eNB (more than 1 million in big countries) to an InfoService can lead to huge OPEX/CAPEX to an operator.

Observation 3:

Involving an MME in WT address discovery will make any Signalling-basedSolution Scalable and Secure.

Proposal 2:

RAN3 is respectfully requested to explore whether MME involvement in WTTNL Address discovery is paramount to ensure security and scalability.

Observation 4:

Querying an AP before getting associated by a UE cannot be reallypreferred.

Observation 5:

A UE-based Solution is Simpler only if it can be made Secure.

Proposal 3:

RAN3 is respectfully requested to analyse the pros and cons of theUE-based and the network-based in terms of cost, scalability andsecurity and choose the right Solution.

The following is a detailed description of the way in which the abovedescribed UE mobility related embodiments may be implemented in thecurrently proposed 3GPP standards. Whilst various features are describedas being essential or necessary, this may only be the case for theproposed 3GPP standard, for example due to other requirements imposed bythe standard. These statements should not, therefore, be construed aslimiting the present invention in any way.

1 Introduction

Seamless mobility while having LWA is within the scope of this new WI onLWA. In RAN3 #91bis, several mobility cases had been analysed andsubsequently the following WA was made:

-   -   WA: HO without WT change

Other Scenarios including one that involves WT change can still bewithin the Scope of future discussion based on consensus. This meansthat other mobility scenarios have not been ruled out yet. Any of thesemobility cases however require a Source eNB to first figure out whethera particular UE HO involves WT change OR not. At the moment no priordiscussion has ever considered this.

The objective of this paper is to explore whether any priory informationhas to be in place at the source eNB side for it to execute the correctHO.

2 Discussion

Offloading to WLAN through LWA enables better user experience whileenabling a network operator to manage its scarce and expensive radioresources efficiently. At the time of HO which is triggered mainly basedon signal quality measurement, if a source eNB has extra pieces ofinformation such as residual capacity, load information of each targetcandidate, HO rejection by a target candidate due to lack of resourcescan be avoided. In other words, the extra SON (Self-Organizing Network)information will in turn help a source eNB minimise resource wastage dueto unsuccessful HO attempts while providing better QoE (Quality ofExperience) to a UE.

In a resource constraint target, the luxury of offloading trafficthrough LWA is always helpful. Hence, before deciding a HO type in termsof whether it involves WT change OR not it is better for a Source eNB toknow whether its potential target candidates have connectivity to thesame WT or possibly to the same AP that serves a UE in question.

Observation 1:

Getting a Source eNB to know whether each of its target candidate hasconnectivity to the same WT at the time HO is useful for better resourcemanagement and UE experience.

This means it is better for eNBs to include WT connectivity in itsneighbour information. Although split bearer option is considered in LWAcase where a target can still reset its PDCP (Packet Data ConvergenceProtocol) after a HO, choosing the target that has connectivity to thesame WT is useful as opposed to completely breaking LWA at the time ofHO and making WT additions after a HO. This puts extra effort on UE aswell as on target in terms of measurement taking and signalling.

Proposal 1:

RAN3 is respectfully requested to explore the benefits of including WTdetails in Neighbour Information IE.

3 Conclusion and Proposals

This paper Analyses the need for eNBs to have full picture of neighboursin terms of WT connectivity for better resource usage and UE QoE. Withits basic Analysis, it further makes the following Observation andproposal:

Observation 1:

Getting a Source eNB to know whether each of its target candidate hasconnectivity to the same WT at the time HO is useful for better resourcemanagement and UE experience.

Proposal 1:

RAN3 is respectfully requested to explore the benefits of including WTdetails in Neighbour Information IE.

The whole or part of the example embodiments disclosed above can bedescribed as, but not limited to, the following supplementary notes.

(Supplementary note 1) A base station for a communication network, thebase station comprising:

-   -   a transceiver configured to communicate with a communication        device; and    -   a controller configured to perform an automatic neighbour        relation operation in relation to at least one Wireless Local        Area Network, WLAN;    -   wherein the controller is configured to obtain, from at least        one of the communication device and a mobility management        entity, an address associated with a node of the wireless local        area network, WLAN, and to establish a connection with the node        of the WLAN using the obtained address.

(Supplementary note 2) The base station according to Supplementary note1, wherein the controller is configured to control, using theestablished connection, aggregation of resources for concurrentcommunications via a cell operated by the base station and via an accesspoint of the WLAN.

(Supplementary note 3) The base station according to Supplementary note1 or 2, wherein the controller is configured to obtain, from themobility management entity, the address associated with a node of a WLANby sending, to the mobility management entity, a signalling message fortriggering transfer of the address associated with the node of the WLAN(e.g. an ‘eNB Configuration Transfer’ message or a ‘WT AddressDiscovery’ message).

(Supplementary note 4) The base station according to Supplementary note1 or 2, wherein the controller is configured to obtain, from thecommunication device, the address associated with a node of a WLAN bysending, to the communication device, a message to request that thecommunication device reads the address of the node of the WLAN (readingWLAN information broadcast).

(Supplementary note 5) The base station according to Supplementary note3 or 4, wherein the signalling message includes an identifier foridentifying the WLAN (e.g. a Service Set Identifier, SSID; a HomogenousExtended Service Set Identifier, HESSID; and/or a Basic Service SetIdentifier, BSSID).

(Supplementary note 6) The base station according to any one ofSupplementary notes 1 to 5, wherein the address comprises a transportnetwork layer, TNL, address.

(Supplementary note 7) A base station for a communication network, thebase station comprising:

-   -   a transceiver configured to communicate with a neighbouring base        station; and    -   a controller configured to obtain, from at least one of the        neighbouring base station and an access point of a wireless        local area network, WLAN, information indicating that the        neighbouring base station has a direct connection with a node of        the WLAN.

(Supplementary note 8) The base station according to Supplementary note7, wherein the controller is further configured to obtain at least oneof: information (e.g. a ‘WT ID’) identifying a node of the WLAN, a listof access points of the WLAN; and an identifier for identifying the WLAN(e.g. a Service Set Identifier, SSID; a Homogenous Extended Service SetIdentifier, HESSID; and/or a Basic Service Set Identifier, BSSID).

(Supplementary note 9) A base station for a communication network, thebase station comprising:

-   -   a transceiver configured to communicate with a neighbouring base        station; and    -   a controller configured to obtain, from the neighbouring base        station, information indicating that the neighbouring base        station has a direct connection with a base station that is        operable as a secondary base station, SeNB, in a dual        connectivity, DC, arrangement.

(Supplementary note 10) A mobility management entity for a communicationnetwork, the mobility management entity comprising:

-   -   a controller configured to obtain, upon request by a base        station performing an automatic neighbour relation operation in        relation to at least one wireless local area network, WLAN, an        address associated with a node of the WLAN; and    -   a transceiver configured to send, to the base station, the        obtained address associated with the node of the WLAN.

(Supplementary note 11) The mobility management entity according toSupplementary note 10, wherein the request by the base station comprisesa signalling message for triggering transfer of the address associatedwith the node of the WLAN (e.g. an ‘eNB Configuration Transfer’ messageor a ‘WT Address Discovery’ message).

(Supplementary note 12) The mobility management entity according toSupplementary note 10 or 11, wherein the controller is configured toobtain the address associated with the node of the WLAN from aninformation service or domain name system node (e.g. using anappropriate Fully Qualified Domain Name, FQDN, procedure and/or anAccess Network Query Protocol, ANQP, procedure).

(Supplementary note 13) A communication device for a communicationnetwork, the communication device comprising:

-   -   a controller configured for obtaining, from an access point of a        wireless local area network, WLAN, information identifying an        address of a node of the WLAN; and    -   a transceiver configured to provide the obtained information to        the base station as part of an automatic neighbour relation        operation in relation to the WLAN.

(Supplementary note 14) The communication device according toSupplementary note 13, wherein the controller is further configured foraggregation of resources for concurrent communications via a celloperated by the base station and via an access point of the WLAN.

(Supplementary note 15) The communication device according toSupplementary note 13 or 14, wherein the transceiver is configured toreceive, from the WLAN, an identifier for identifying the WLAN; and toprovide the received identifier to the base station in a measurementreport.

(Supplementary note 16) The communication device according toSupplementary note 15, wherein the transceiver is configured to receive,from the base station after sending the measurement report, a message torequest that the communication device reads the address of a node of theWLAN identified by the identifier; and wherein the controller isconfigured to perform said obtaining of the address of the node of theWLAN in response to the request message.

(Supplementary note 17) The communication device according toSupplementary note 16, wherein the received message is furtherconfigured to request that the communication device reads at least oneof: information (e.g. a PLMN-ID) identifying a public land mobilenetwork, PLMN, associated with the WLAN; information identifying thatthe access point supports LTE-WLAN Aggregation, LWA, functionality (e.g.an ‘LWA-Support Indicator’); and information (e.g. a ‘WT ID’)identifying the node of the WLAN; and wherein the controller isconfigured to obtain at least one of: the information identifying a PLMNassociated with the WLAN; the information identifying that the accesspoint supports LWA functionality; and the information identifying thenode of the WLAN.

(Supplementary note 18) An access point for a communication network, theaccess point comprising:

-   -   a transceiver configured to broadcast an address of a node of a        wireless local area network, WLAN, to which the access point        belongs.

(Supplementary note 19) The access point according to Supplementary note18, wherein the transceiver is further configured to broadcast at leastone of: information (e.g. a PLMN-ID) identifying a public land mobilenetwork, PLMN, associated with the WLAN; information identifying thatthe access point supports LTE-WLAN Aggregation, LWA, functionality (e.g.an ‘LWA-Support Indicator’); and information (e.g. a ‘WT ID’)identifying the node of the WLAN.

(Supplementary note 20) A system comprising: the base station accordingto any one of Supplementary notes 1 to 9; the mobility management entityaccording to any one of Supplementary notes 10 to 12; and acommunication device.

(Supplementary note 21) A system comprising: the base station accordingto any one of Supplementary notes 1 to 9; a mobility management entity;the communication device according to any one of Supplementary notes 13to 17; and the access point according to Supplementary note 18 or 19.

(Supplementary note 22) A method performed by a base station of acommunications network, the method comprising:

-   -   performing an automatic neighbour relation operation in relation        to at least one Wireless Local Area Network, WLAN;    -   obtaining, from at least one of a communication device and a        mobility management entity, an address associated with a node of        the WLAN; and    -   establishing a connection with the node of the WLAN using the        obtained address.

(Supplementary note 23) A method performed by a base station of acommunications network, the method comprising:

-   -   obtaining, from a neighbouring base station, information        indicating that the neighbouring base station has a direct        connection with a node of a wireless local area network, WLAN.

(Supplementary note 24) A method performed by a base station of acommunications network, the method comprising:

-   -   obtaining, from the neighbouring base station, information        indicating that the neighbouring base station has a direct        connection with a base station that is operable as a secondary        base station, SeNB, in a dual connectivity, DC, arrangement.

(Supplementary note 25) A method performed by a mobility managemententity of a communications network, the method comprising:

-   -   obtaining, upon request by a base station performing an        automatic neighbour relation operation in relation to at least        one wireless local area network, WLAN, an address associated        with a node of the WLAN; and    -   sending, to the base station, the obtained address associated        with the node of the WLAN.

(Supplementary note 26) A method performed by a communication device,the method comprising:

-   -   obtaining, from an access point of a wireless local area        network, WLAN, information identifying an address of a node of        the WLAN; and    -   providing the obtained information to the base station as part        of an automatic neighbour relation operation in relation to the        WLAN.

(Supplementary note 27) A method performed by an access node, the methodcomprising:

-   -   broadcasting an address of a node of a wireless local area        network, WLAN, to which the access point belongs.

(Supplementary note 28) A computer program product comprising computerimplementable instructions for causing a programmable computer device toperform the method according to any one of Supplementary notes 22 to 27.

While the invention has been particularly shown and described withreference to example embodiments thereof, the invention is not limitedto these embodiments. It will be understood by those of ordinary skillin the art that various changes in form and details may be made thereinwithout departing from the sprit and scope of the present invention asdefined by the claims.

This application is based upon and claims the benefit of priority fromUnited Kingdom Patent Application No. 1608492.3, filed on May 13, 2016,the disclosure of which is incorporated herein in its entirety byreference.

1. A method performed by a base station of a communications network, themethod comprising: establishing an Xw connection with a WLANTermination, ‘WT’, node of a wireless local area network, ‘WLAN’; andobtaining, from the WT node, in an Xw Setup Response message or a WTConfiguration Update message, information indicating at least oneneighbouring base station that has a connection with the WT node.
 2. Themethod according to claim 1, further comprising obtaining, from the WTnode, at least one of: information identifying the WT node; a list ofaccess points of the WLAN; and an identifier for identifying the WLAN.3. The method according to claim 1, wherein the identifier foridentifying the WLAN comprises at least one of: a Service SetIdentifier, ‘SSID’; a Homogenous Extended Service Set Identifier,‘HESSID’; and/or a Basic Service Set Identifier, ‘BSSID’.
 4. The methodaccording to claim 1, further comprising performing a handover procedurebased on the obtained information.
 5. A method performed by a WLANTermination, ‘WT’, node of a wireless local area network, ‘WLAN’, themethod comprising: establishing an Xw connection with a base station;and sending, to the base station, in an Xw Setup Response message or aWT Configuration Update message, information indicating at least oneneighbouring base station that has a connection with the WT node.
 6. Themethod according to claim 5, further comprising sending, to the basestation, at least one of: information identifying the WT node; a list ofaccess points of the WLAN; and an identifier for identifying the WLAN.7. The method according to claim 5, wherein the identifier foridentifying the WLAN comprises at least one of: a Service SetIdentifier, ‘SSID’; a Homogenous Extended Service Set Identifier,‘HESSID’; and/or a Basic Service Set Identifier, ‘BSSID’.
 8. A basestation for a communication network, the base station_comprising: a basestation interface configured to establish an Xw connection with a WLANTermination, ‘WT’, node of a wireless local area network, ‘WLAN’; amemory having stored therein program instructions; and a controllerconfigured to execute the program instructions stored in the memory andupon execution of the program instructions obtaining, from the WT node,in an Xw Setup Response message or a WT Configuration Update message,information indicating at least one neighbouring base station that has aconnection with the WT node.
 9. The base station according to claim 8,wherein the controller is further configured to obtain, from the WTnode, at least one of: information identifying the WT node, a list ofaccess points of the WLAN; and an identifier for identifying the WLAN.10. The base station according to claim 8, wherein the identifier foridentifying the WLAN comprises at least one of: a Service SetIdentifier, ‘SSID’; a Homogenous Extended Service Set Identifier,‘HESSID’; and/or a Basic Service Set Identifier, ‘BSSID’.
 11. The basestation according to claim 8, wherein the controller is furtherconfigured to perform a handover procedure based on the obtainedinformation.
 12. A WLAN Termination, ‘WT’, node of a wireless local areanetwork, ‘WLAN’, the WT node comprising: a transceiver configured tosend, to a base station, in an Xw Setup Response message or a WTConfiguration Update message, information indicating at least oneneighbouring base station that has a connection with the WT node. 13-15.(canceled)